When it comes to a numeric limitation on the allowable level of turbidity in discharges from certain construction sites, the industry may not be out of the woods yet. Although the U.S. Environmental Protection Agency (EPA) earlier this month withdrew the limitation and monitoring requirements, EPA emphasized that it may “decide to propose and promulgate additional effluent limitations guidelines and monitoring requirements in a future rulemaking,” … and the industry is concerned.

Associated General Contractors of America (AGC), which estimated that a numeric effluent limit (NEL) for turbidity on construction sites nationwide would have cost the industry about $10 billion a year to achieve compliance, “remains concerned about EPA’s ongoing effort to collect data and perhaps develop a new NEL at some point in the future,” Leah Pilconis, a consultant on environmental law and policy and a senior environmental advisor to AGC, told ConstructionPro Week (CPW).

The issue has its roots in a 2009 EPA final rule (40 Code of Federal Regulations/CFR 450) addressing stormwater discharges from the “construction and development” (C&D) point source category. The rule required owners and operators of permitted construction activities to implement erosion and sediment controls, stabilize soils, manage dewatering activities, implement pollution-prevention measures, provide and maintain buffers around surface waters, prohibit certain discharges, and use surface outlets for discharges from basins and impoundments. In addition, the 2009 Effluent Limitation Guideline (ELG) set a numeric standard of 280 nephelometric turbidity units.

After the 2009 C&D rule was issued, several parties filed petitions for review of the final rule, identifying potential deficiencies with the dataset that EPA used to support its decision to adopt the numeric turbidity limitation as well as other issues. In December 2012, EPA entered into a settlement agreement with petitioners to resolve litigation. The new final rulemaking, issued March 6, satisfies EPA’s agreements under the litigation.

The final change removes the numeric discharge standard and monitoring requirements previously found at 40 CFR 450.22(a) and 450.22(b). Although withdrawing the numeric limitation, EPA explained that it “has reserved these paragraphs for potential revisions should we decide to propose and promulgate additional effluent limitations guidelines and monitoring requirements in a future rulemaking. We are considering data and comments submitted in response to the Jan. 3, 2012, Federal Register notice (77 FR 112) seeking additional information and data on numeric standards.”

EPA reported that it received several comments on the issue. “While many commenters were supportive of removing the numeric turbidity effluent limitation and monitoring requirements, some commenters were opposed to this and requested that we reinstate a numeric limitation.”

If EPA opts to pursue reinstatement of a limitation, though, it may take a while. “At a meeting between AGC members and EPA staff that took place last summer, EPA indicated that it was not currently working on a new numeric limit,” Pilconis said. “For the effort to pick back up, EPA would need to collect a lot more data.”

The ConstructionPro Network member version of this article includes a transcript of CPW's interview with Pilconis and additional details about the rule.